1600dp DVDA odd timing issue

[asiab3]

Problem Solved!

There is (too much, I think) play between my drive gear and crank gear, but having the spring set correctly between the distributor drive tang and drive gear negates that play and allows the advances to be smooth and consistent in both directions. My distributor spring was pushed so far into the drive grar, that it wasn't functioning. I don't know how it got that way. By pulling it out (oddly tough) and resetting it gently in the center and installing the distributor, the DVDA functions smoothly and offers great drivability.

I hope this improves our dismal .00071% reporting rate as of 11/08/13!

Robbie

[Amskeptic]

Problem Solved!

There is (too much, I think) play between my drive gear and crank gear, but having the spring set correctly between the distributor drive tang and drive gear negates that play and allows the advances to be smooth and consistent in both directions. My distributor spring was pushed so far into the drive grar, that it wasn't functioning. I don't know how it got that way. By pulling it out (oddly tough) and resetting it gently in the center and installing the distributor, the DVDA functions smoothly and offers great drivability.

I hope this improves our dismal .00071% reporting rate as of 11/08/13!

Robbie

Well, you have single-handledly improved the Technical Forums Compliance Rate up to .0039 %

That spring is an important part of reducing "scatter" since we are dealing with what is essentially a worm drive in the brass gear. I do not know of a "specification" for free or compressed spring length/pressure, but you do know, deep in the nagging reminder corner of your mind, that your gently seated spring will work its way down again. So, you need to pull the intermediate drive gear, clean the spring hole, make the spring find its true seat, establish the correct length projection (too much will destroy the distributor thrust washers, fiber washer and distributor body), and reassemble all by the end of winter.

Or you could just monitor the situation and know that a bit of thrust pressure keeps the gears in correct mesh. Too much endplay will cause scatter than you cannot remedy . . .
Colin

[kreemoweet]

I have a couple dist. drive pinions and a spring at hand. The pinions are clearly Genuine VW, but I cannot vouch for the spring. The spring measures about 6.3 mm diam.
and 24.5 mm long. It bottoms easily in the spring holes of both pinions, and protrudes from the tops of same about 6.5 mm. When compressed to within about .5 mm
of the pinion top (as it would be when installed with distributor in place), it exerts a force of about 3.9 - 4.5 pounds, as measured on a non-too-accurate kitchen scale.
It would be interesting to hear if others have significantly different results.

[Amskeptic]

I have a couple dist. drive pinions and a spring at hand. The pinions are clearly Genuine VW, but I cannot vouch for the spring. The spring measures about 6.3 mm diam.
and 24.5 mm long. It bottoms easily in the spring holes of both pinions, and protrudes from the tops of same about 6.5 mm. When compressed to within about .5 mm
of the pinion top (as it would be when installed with distributor in place), it exerts a force of about 3.9 - 4.5 pounds, as measured on a non-too-accurate kitchen scale.
It would be interesting to hear if others have significantly different results.

Well, here is the definitive scientific test.
Thank-you.
Colin

[asiab3]

l'll test my spare genuine VW parts sometime soon.

I'm also curious how whatever franken-drive system I have right now allowed my spring to sink down and get caught like it did.